Extinction and dawn of the modern world in the Carnian (Late Triassic)

The Carnian Pluvial Episode (Late Triassic) was a time of global environmental changes and possibly substantial coeval volcanism. The extent of the biological turnover in marine and terrestrial ecosystems associated with these events is, however, still not well understood. In this review, we present a meta-analysis of fossil data that suggests a substantial reduction in generic and species richness in many marine groups and an overall disappearance of 33% of all marine genera at this time. This crisis coincides with a major turnover in terrestrial ecosystems during the Carnian. The extinction is associated with a major radiation event. In the sea, the rise of the first scleractinian reefs and the first rock-forming accumulations of calcareous nannofossils, point to significant changes in ocean chemistry. On land, there were major diversifications and originations of conifers, insects, dinosaurs, crocodiles, lizards, turtles, and mammals. Although there still is uncertainty on the precise age of some of the recorded biological changes, these observations indicate that the Carnian Pluvial Episode was linked to a major extinction event and might have been the trigger of the spectacular radiation of many key groups that dominate modern ecosystems.